In recent years, occasions in which imaging devices such as digital still cameras and the like are employed in environments where electromagnetic wave-radiating handheld information terminals such as mobile phones and PHS's (Personal Handyphone Systems) are used are increasing. In addition, occasions in which imaging devices such as digital still cameras and the like are employed in environments, including the vicinity of radio broadcasting stations and television broadcasting stations, for example, where strong electromagnetic waves are radiated are also increasing.
When the imaging devices are used under such environments, the imaging devices may be subjected to electromagnetic wave interference. Such an environment where the imaging devices may be subjected to electromagnetic wave interference is referred to as “a strong electric field environment.” If imaging devices such as digital still cameras and the like are used in a strong electric field environment, there are cases where picture (or video) interference occurs, such that images taken by the imaging devices contain striped-pattern noise (beat noise).
The picture (or video) interference becomes more prominent when the imaging elements that the imaging devices contain are high-performance (through having high sensitivity). Furthermore, associated with miniaturization of the imaging devices, the amount of external strong-electric-field noise coupled to the imaging elements incorporated in the miniaturized imaging devices increases, such that the picture (or video) interference becomes more prominent.
Causes of such picture (or video) interference include penetration of external electromagnetic waves into video signal lines of the imaging elements, or fluctuation of the ground (“GND”) potential of imaging element flexible cables due to the influence of external electromagnetic waves.
Therefore, it has been necessary to take measures such as reducing the GND impedance of the imaging element flexible cables, or shielding the imaging elements along their periphery.
Another measure for reducing the picture (or video) interference is to connect a heat dissipation plate to the main board by using, for example, electrically conductive elastic members such as metal springs. However, with this measure, stress is applied on the imaging elements in the traveling direction of light, and thereby the imaging elements will tilt. As a result, deterioration of image quality occurs in images taken by the imaging devices, and therefore it has been difficult to introduce the measure in actual products.
Therein, configurations that have been used in conventional technology include a configuration of covering the entirety of an imaging device with a cover consisting of an electrically conductive medium, a configuration of adding an electrically conductive filter to the surface of the lens to shield the imaging elements against the entry of strong electric field noise (cf., for example, Patent Literature 1), and a configuration of forming a shield along the periphery of the imaging elements.